What specific promise did Cholkar make to Baba, and what personal sacrifice did he undertake when he couldn't fulfill it immediately?

According to Chapter 15, Cholkar's promise, or vow, to Sai Baba was that if he passed a crucial examination for his job, he would "present myself at your feet And distribute sugar candy (khadisakhar) in your name." After passing, he was unable to make the journey to Shirdi right away due to financial constraints. To honor his commitment during this delay, he made a personal sacrifice by giving up sugar entirely. The text explicitly states that until the vow was fulfilled, "Cholkar avoided sugar as an inedible substance, And even drank his tea without sugar." This secret penance made Baba's later actions even more meaningful.